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Hippocrates noted that blood separates into four differently colored liquids when removed from the body and examined: a pure red liquid mixed with white liquid material with a yellow-colored froth at the top and a black substance that settles underneath; he named these the four humors (for blood, phlegm, yellow bile, and black bile).
When blood is exposed to air, it clots. Heparin allows the blood to come in direct contact with air without clotting.
Nearly 31 million adults in America have a total cholesterol level that is more than 240 mg per dL.
More than 4.4billion prescriptions were dispensed within the United States in 2016.
Pope Sylvester II tried to introduce Arabic numbers into Europe between the years 999 and 1003, but their use did not catch on for a few more centuries, and Roman numerals continued to be the primary number system.